Asked at a round-table debate organised by the New Statesman magazine whether demand would always increase to fill whatever capacity the NHS could offer, he said this could be a factor.

'We may already be seeing this with a somewhat mysterious rise in GP referrals in some PCTs. It would seem that part of it is that GPs are actually referring, whereas before they would not have bothered because the person would have had to wait too long,' he said.

He defended extended opening hours, saying that not only well-off commuters had benefited from the change.

'The anecdotal evidence is that it is blue-collar workers using the services because they are paid by the hour and otherwise they would lose pay.'